The present invention relates to an information processing apparatus to be connected to a digital communication line to communicate data, and in particular, to a technology effective to control the life of batteries in a battery-driven hand-held information processing apparatus including a digital communication line inter ace circuit to be connected to a network such as a local area network to communicate data.
In use of conventional information processing apparatuses or processors, a plurality of information processors are connected to a network such that various data items are communicated between the plural information processors.
The information processor connected to the network to communicate data as above includes a digital communication line interface circuit to be connected to the digital communication line.
For the interface above, there exists recently a tendency that the transfer speed is considerably improved and the power consumption is conspicuously increased due to the direct connection to a high-speed bus.
Presently, when a digital communication line interface circuit is installed in a battery-driven hand-held information processor, the ratio of power consumption of the interface circuit takes quite a large value in the overall power consumption of the information processor.
In the case of the battery-driven information processor, the digital communication interface circuit is used primarily in an office environment and, hence, when the apparatus is being carried about and is driven by batteries, the interface circuit is not connected to a digital communication line such as a network in many cases. Therefore, in general, when the information processor is being carried about, the interface circuit is not used.
Consequently, when the battery-driven information processor is being carried about and is driven by batteries, it can be considered to elongate the battery drive time by stopping the interface circuit not used. However, in the conventional information processor, to stop only the line interface circuit when the line is not used, there arises a difficulty. Namely, it is necessary to provide a sleep signal and a circuit or the like to relate the signal to a link signal.
On the other hand, in JP-A-61-173578, there has been described a communication start/end scheme for use with an apparatus in which a telephone line is shared between a telephone set and a data terminal, the method remarkably lower power consumption of the apparatus and simplifying the function to identify a call termination and the function to monitor the end of call.
According to the apparatus of JP-A-61-173568, a logic to distinguish a telephone call from a data communication and a logic to monitor the end of call are disposed in a read-only memory (ROM), and the apparatus is entirely powered at call termination such that the start or end of call is awaited according to the logic in association with activation of the ROM to interrupt power, only excepting the line interface section, so as to set the apparatus to a standby state.
The present inventors have considered the prior art, and have found the following problems.
That is, in the conventional information processor, since it is difficult to stop only the digital communication line interface circuit when the digital communication line is not used, there has been a problem that the power consumption of the interface circuit cannot be minimized even when the information processor is used for a purpose other than for digital communication.
Furthermore, when the conventional information processor is driven by batteries, the interface circuit continuously consumes a large amount of power even when the digital communication line is not used, which raises a problem of a short battery life and a minimized battery drive time.
Additionally, in the conventional information processor, even when the digital communication line is not used, the digital communication line interface circuit continuously uses the hardware resource to establish an interruption signal, an address space, and the like, which therefore results in a problem of restriction in expandability of the information processor.
On the other hand, in the conventional communication start/end method of JP-A-61-173568, there are effected reduction of power consumption of the processor when externally accessing a host via a telephone line, and simplification of the function to identify a call termination and the function to monitor the end of call, which leads to a problem that power cannot be turned on or off in response to an access from the host side.
It is therefore an object of the present invention to provide a hand-held information processing apparatus capable of controlling power consumption of the digital communication line interface circuit in accordance with a utilization state of the digital communication line.
Another object of the present invention is to provide an information processing apparatus capable of controlling power consumption of the digital communication line interface circuit in accordance with a change in the state of other information processing apparatus on the network.
Another object of the present invention is to provide an information processing apparatus capable of controlling power consumption of the digital communication line interface circuit not including a power source line and a sleep mode signal line.
Another object of the present invention is to provide a technology capable of efficiently using resources of the information processing apparatus.
The above and other objects and novel features of the present invention will be clarified through description and accompanying drawings of this specification.
Of the present invention disclosed by this application, an outline of representative aspects will be briefly described herebelow.
(1) An information processing apparatus including a digital communication line interface circuit to be connected to a digital communication line to communicate data includes means to change a consumption power mode of the interface circuit in accordance with a link state with respect to the communication line.
In the information processing apparatus, when a particular link state confirmation request (reference numeral 301 or 211 herebelow) is issued, a link state detect circuit checks to determine whether a link is already established between the interface circuit and the communication line.
In this regard, the confirmation request is issued in response to a transition of a power management mode, an input of a line confirmation request by an operator, a power-on operation, a detection of a reception signal at a particular level, an operation to attach or to remove a network cable, or a change in the power source supply method.
If the link has been established between the interface circuit and the communication line, the consumption power mode change circuit keeps the supply of power to the interface circuit.
If the link has not been established between the interface circuit and the communication line, the consumption power mode change circuit changes the mode of the power supply to the interface circuit to the low consumption power mode.
In this situation, the meaning of the consumption power mode to be changed by the mode change circuit varies depending on the type of the signal line included in the interface circuit. For example, when the interface circuit includes only a power source line, the consumption power mode can be changed by the power-on or power-off operation.
Furthermore, when there is disposed a sleep mode signal line to change the mode of the interface circuit to the sleep mode, the consumption power mode can be changed in accordance with the sleep mode.
As above, in accordance with the information processing apparatus, since the power consumption of the digital communication line interface circuit is minimized when there is not established a link with the digital communication line, it is possible to control the power consumption of the line interface circuit in accordance with the utilization state of the digital communication line.
(2) The information processing apparatus described in the aspect (1) above includes means (e.g., a circuit 300 of FIG. 3) to confirm the link state with the digital communication line in response to detection of a change in the particular reception signal level (exceeding a threshold).
In the information processing apparatus, the reception signal level detector circuit checks the signal level of the reception signal received by the interface circuit to thereby conduct a monitor operation to determine whether or not a signal having a particular amplitude is being transmitted through the digital communication line.
When a transmission of the signal having the particular amplitude is started through the communication line or a transmission of the signal having the particular amplitude conducted through the communication line is stopped, the link state detect circuit confirms the link state with respect to the communication line.
If the information processing apparatus has been connected via an inter-network apparatus such as a hub, a bridge, a router, or a local area network (LAN) switch to a network, the state of the link between the information processing apparatus and the communication line is changed when the power of the inter-network apparatus is turned on or off.
In this case, the reception signal level detector circuit of the information processing apparatus detects, in accordance with the change in the reception signal level, that the power of the inter-network apparatus installed between the network and the information processing apparatus is turned on or off, and then issues a link state confirmation request to thereby change the consumption power mode.
As above, in accordance with the information processing apparatus, since the link state is confirmed at detection of the reception signal at a particular level on the digital communication line, the power consumption of the interface circuit can be controlled corresponding to a change in the state of other processing apparatus on the network.
(3) The information processing apparatus described in the aspect (1) or (2) includes means for changing the consumption power mode by keeping the reset signal.
When changing the consumption power mode of the interface circuit in the information processing apparatus, the reset signal is held or is released by the reset signal hold circuit to change the consumption power made of the interface circuit.
When a reset signal is inputted to the interface circuit, the internal state of the interface circuit is initialized, namely, the interface circuit is set to a state in which the interface circuit does not operate while the reset signal is being inputted thereto.
Therefore, when the state in which the reset signal is being inputted is held in the interface circuit, the state in which the interface circuit does not operate is held, which establishes the state of the low consumption cower mode.
As above, in accordance with the information processing apparatus, since the consumption power is controlled by the reset signal, it is possible to control the consumption power of the digital communication line interface circuit having no power source line or sleep mode signal line.
(4) The information processing apparatus in accordance with the aspect (1), (2), or (3) includes means for changing the resource allocation when the consumption power mode is changed.
In the information processing apparatus, when the consumption power mode of the interface circuit is changed by the consumption power mode change circuit, the allocation of resources allocated to the interface circuit is changed by a resource allocation controller.
In the information processing apparatus, when the operation of the interface circuit is stopped due to occurrence of a particular link state confirmation request, an interruption signal and an I/O address employed by the interface circuit are set to an unused state.
Consequently, when starting the operation of another circuit by the consumption power mode change circuit, the interruption signal and the I/O address in the unused state can be allocated to the circuit for the operation.
For example, if the resources allocated to the interface circuit are allocated to the pertinent circuit for the operation, the resources can be deallocated and allocated to the circuit and the interface circuit by alternatively activating operation of the circuit and the interface circuit by the resource allocation controller.
As above, in accordance with the information processing apparatus, since the resource allocation is changed when the consumption power mode is changed, the resources of the information processing apparatus can be efficiently utilized.